Recently, a liquid crystal display apparatus is widely used, because the liquid crystal display apparatus has lightweight, thin thickness and low power consumption.
The liquid crystal display apparatus includes a liquid crystal display panel and a backlight assembly. The backlight assembly provides light to the liquid crystal display panel. The liquid crystal display panel includes a color filter substrate and an array substrate. The color filter substrate includes color filters through which the light having specific wavelengths may pass to display colored images. The color filter includes a common electrode. A reference voltage is applied to the common electrode.
The array substrate employs a thin film transistor as a switching device. The thin film transistor includes a gate electrode, a drain electrode and a source electrode. The gate electrode is electrically connected to a gate line. The drain electrode is electrically connected to a pixel electrode. The source line is electrically connected to a data line. When a gate voltage is applied to the gate line, the thin film transistor is turned on, so that a pixel voltage is applied to the pixel electrode via the thin film transistor.
A liquid crystal layer is interposed between the color filter substrate and the array substrate. When the pixel voltage is applied to the pixel electrode, electric fields are formed between the pixel electrode and the common electrode. The electric fields change the arrangement of the liquid crystal molecules of the liquid crystal layer to change the transmittance of light provided from the backlight assembly. Therefore, an image is displayed.
According to the conventional liquid crystal display apparatus, the data line does not overlap with the pixel electrode to avoid the increase in power consumption from the cross-talk due to the parasitic capacitance formed between the data line and the pixel electrode when the data line overlaps with the pixel electrode.
However, when the data line does not overlap with the pixel electrode, the distance between the pixel electrodes increases due to the data line that is disposed between the pixel electrodes. Therefore, aperture ratio is lowered. Furthermore, the light leakage between the data line and the pixel electrode causes lower luminance.
In order to avoid above-mentioned problems, an insulation layer is formed between the data line and the pixel electrode. Therefore, a portion of the data line may overlap with the pixel electrode to increase the aperture ratio.
The insulation layer has a low dielectric constant. Furthermore, when the insulation layer is formed, the distance between the data line and the pixel electrode increases. Therefore, even when a portion of the data line overlaps with the pixel electrode, a parasitic capacitance formed between the data line and the pixel electrode becomes negligibly small. Therefore, the insulation layer formed between the pixel electrode and the data line increases the aperture ratio and prevents the leakage of the light from the backlight assembly.
However, when the insulation layer is formed, the bonding strength between the sealant that combines the color filter substrate and the array substrate, and the insulation layer, or the bonding strength between the insulation layer and the gate insulation layer becomes fragile. Thus, a weak impact may separate the color filter substrate from the array substrate. Even though the color filter substrate is not completely separated from the array substrate, liquid crystal material is not completely injected into between the color filter substrate and the array substrate due to the crack formed between the sealant and the insulation layer or between the insulation layer and the gate insulation layer, which lowers the productivity.